JP5154011B2 - Flexible flat cable - Google Patents

Description

The present invention relates to a superior flexible flat cable to the corrosion resistance and insertion durability.

  Copper and copper alloys are often used as wiring for components and wiring boards used in electronic devices and the like. When these are electrically connected to other wiring boards or the like, many connectors are connected in addition to bonding by metal bonding such as soldering or ultrasonic bonding. When the connector is connected, the copper wiring terminal is usually subjected to a surface treatment in order to reduce the contact resistance between the wiring and the connector to eliminate the conduction failure. For example, electrolytic plating treatment with gold, tin-palladium alloy or the like. However, gold plating has a problem of high cost, and in the plating treatment with an alloy containing lead, it has been pointed out that lead is eluted and pollutes the environment, and lead-free is also desired. For this reason, pure tin plating and tin alloy-based plating not containing lead have been studied. However, in the case of pure tin plating or tin alloy plating that does not contain lead, when the copper wiring terminal part is fitted to the connector, it is called a whisker because of the plating film around the portion pressed by the connector pin. It has been confirmed that crystal-like crystals are rapidly generated. The generation of such whiskers has a problem that leads to a short circuit between the wirings. It has also been found that the above phenomenon is remarkable in pure tin plating and tin-based alloy plating not containing lead. For this reason, gold / nickel (hereinafter referred to as Au / Ni) is also considered as a surface treatment for copper wiring terminals, but gold / nickel (hereinafter referred to as Au / Ni) is also considered. There is. This is undesirable because it increases the contact resistance. However, since Au plating is expensive, it is not preferable to increase the thickness because it increases the product cost.

On the other hand, in order to improve the bondability of wire bonding, an electroless nickel plating film, a substituted palladium plating film, an electroless palladium plating film, a displacement gold plating film, and an electroless gold plating film are formed in this order on the copper surface. It can be seen in Patent Document 1 that this is good. However, this technique is good from the viewpoint of securing contact resistance, but if insertion and removal are repeated a plurality of times to perform connector fitting, there is a problem in that contact resistance is caused due to insufficient wear resistance.
Japanese Patent Laid-Open No. 9-8438

Therefore, the problem to be solved by the present invention is to provide a terminal portion of a flexible flat cable that is excellent in corrosion resistance, has good insertion / extraction characteristics with a connector, and does not generate cracks after insertion / extraction. Further to provide in addition to the above effects, the flexible flat cable is not the contact resistance even if exposed to the air is increased considerably.

The problem to be solved is, as described in claim 1, wherein a nickel plating layer having a thickness of 0.3 to 1.5 μm is formed on a copper or copper alloy conductor , and then nickel or cobalt is formed. the is characterized by using a palladium based alloy plating layer having a thickness of 0.03 to 0.2 [mu] m were made form flat conductor containing 0.1 to 1 wt%, and the connector insertion type flexible flat cable Is solved.

Also as described in claim 2, wherein the palladium based on the alloy plating layer, according to claim 1, a gold plating layer having a thickness of 0.005~0.20μm is formed connector insertion type flexible flat cable by the, it is solved.

According to the present invention as described above, a nickel plating layer having a thickness of 0.3 to 1.5 μm is formed on a copper or copper alloy conductor , and then 0.1 to 1% by mass of nickel or cobalt. which comprises using a palladium-based alloy plating layer having a thickness of 0.03 to 0.2 [mu] m were made form flat conductor containing, for a connector insertion type flexible flat cable (hereinafter referred to as "FFC"), Excellent corrosion resistance, no significant increase in contact resistance in a corrosive environment, and the formation of a palladium- based alloy plating layer with a specific thickness on it improves the insertion / extraction characteristics of the connector. However, a significant increase in contact resistance can be prevented. Furthermore, no cracks occur after insertion / extraction.

Further, the palladium-based alloy plating layer, since the gold plating layer having a thickness of 0.005～0.20Myuemu (hereinafter referred to as "Au plating layer") is formed FF C, in addition to the above-described characteristics, A significant increase in contact resistance after exposure to the atmosphere can be eliminated.

Further, as the Pd-based alloy plating layer, a palladium-based alloy (hereinafter referred to as “Pd-based alloy”) containing 0.1 to 1 % by mass of nickel (hereinafter referred to as “Ni”) or cobalt (hereinafter referred to as “Co”). By using the used FFC terminal portion, the corrosion resistance is further improved, and the insertion / extraction characteristics with the connector are further improved. Moreover, the FFC terminal part which does not generate | occur | produce the crack after insertion / extraction can be obtained reliably. Furthermore, the FFC terminal portion having the Au plating layer can eliminate a significant increase in contact resistance after exposure to the atmosphere.

The present invention is described in detail below. According to the first aspect of the present invention , a Ni plating layer having a thickness of 0.3 to 1.5 μm is formed on a copper or copper alloy conductor , and then 0.1 to 1% by mass of Ni or Co is contained. which comprises using a thickness from 0.03 to 0.2 rectangular conductor that Pd-based alloy plating layer is made forms of μm to a connector insertion type FF C. In order to improve the insertion / extraction characteristics with the connector, the terminal part that exposed the flat conductor of the FFC in order to improve the insertion / extraction characteristics with the connector has been achieved. This is obtained as a result of examining the problem of contact failure due to insufficient wear resistance when the connector is repeatedly inserted and removed many times in this technology.

That is, as a result of various studies to solve the above-mentioned problems, a Ni plating layer having a thickness of 0.3 to 1.5 μm is formed on the copper or copper alloy conductor , and then Ni or Co is formed. Since it is a connector insertion / extraction type FFC using a rectangular conductor in which a Pd-based alloy plating layer having a thickness of 0.03 to 0.2 μm and containing 0.1 to 1% by mass is formed , wear resistance It has been found that the contact resistance can be prevented from significantly increasing even when the connector is repeatedly inserted and removed many times, and that no cracks are generated after the insertion and removal. By setting the thickness of the Ni plating layer to 0.3 μm or more, it is possible to prevent Cu from diffusing from the base and reaching the surface of the plating layer to impair the corrosion resistance of the Pd-based alloy plating layer or the Au plating layer. In addition, it was confirmed that, by setting the thickness to 1.5 μm or less, cracks are not generated even by bending that may be applied when mated with the connector. Further, the thickness of the Pd-based alloy plating layer is set to 0.03 μm or more so that the wear resistance by inserting and removing the connector can be maintained, and the thickness is set to 0.2 μm or less. This is because if this is exceeded, a problem arises in cost. By the FF C having the above configuration eliminates the problem of significant increase in contact resistance with excellent corrosion environment corrosion resistance, also insertion property of the connector is improved, contact resistance even after repeated insertion and removal of a number of times Can be prevented, and further, no cracks are generated even after many insertions and removals.

Also as described in claim 2, the Pd-based alloy plating layer, the Au plating layer having a thickness of 0.005~0.20μm is formed, in addition to the effects described above, after exposure to the atmosphere can be a significant increase in contact resistance is not FF C. That is, on the copper or copper alloy wiring FFC terminal portion to be fitted with the connector, Ni plating layer having a thickness of 0.3 to 1.5 [mu] m,-out thickness 0.03 to 0.2 [mu] m Me of Pd-based alloy By providing an Au plating layer having a thickness of 0.005 to 0.20 μm after providing the layer, the rate of increase in contact resistance can be made extremely small even if an atmospheric exposure test for 180 days is performed. This is because the organic substance is likely to be adsorbed on the surface of the Pd-based alloy plating layer, and this adsorption of the organic substance affects the contact resistance, but this problem can be eliminated by forming the Au plating layer. . Further, since the Au plating layer is not provided on the Ni plating layer as in the prior art, the corrosion problem due to pinholes does not occur even if the Au plating layer is relatively thin. If the thickness is less than 0.005 μm, the effect of the atmospheric exposure test cannot be sufficiently obtained, and if an Au plating layer having a thickness of 0.20 μm or more is formed, the product cost increases.

And by making the said Pd base alloy plating layer into the FFC terminal part using the Pd base alloy containing 0.1 to 1 mass% of Ni or Co, there is no remarkable increase in contact resistance in a corrosive environment with excellent corrosion resistance. In addition, the insertion / extraction characteristics with the connector are improved, and a significant increase in contact resistance can be prevented even if the insertion / extraction is repeated many times. Furthermore, it is possible to reliably obtain an FFC terminal portion that does not generate cracks even after many insertions and removals. That is, as the Pd-based alloy for forming the Pd-based alloy plating layer, 0.1 to 1% by mass of Ni or Co is included to improve the wear resistance by alloying. The content of Ni or Co is its effect is less than 0.1 wt% not name enough.

Briefly described FFC pin portion, flat conductor for FFC, after plated with Ni in a round copper wire usually about Fai0.5～1Mm, subjected to wire drawing to about Φ0.1~0.2mm These are further converted into flat conductors by rolling. Then, about 10 to 50 of these rectangular conductors are usually arranged in parallel and laminated with a plastic insulating tape to form an FFC. By removing this terminal insulating tape, the Ni-plated Cu conductor is exposed. used as FFC pin portion by.

The effects of the present invention were confirmed by the examples and comparative examples described in Table 1. That is, a Cu wire rolled with Ni plating was processed into a rectangular shape having a width of 0.3 mm and a thickness of 0.05 mm to obtain a rectangular conductor. This was placed in parallel twenty, to prepare a FFC subjected to lamination with polyester insulating tape, and an FFC pin portion to expose the Cu conductor insulation tape was removed was Ni plated of the terminal portion. This FFC pin portion, and a sample to form a plating layer of Pd-based alloy described in various thicknesses in Table 1. Next, this sample was fitted into a non-ZIF type connector plated with Au / Ni (Au plating thickness: 0.3 μm, Ni plating thickness: 3 μm), and in an atmosphere of 10 ppm hydrogen sulfide and 85% humidity for 48 hours. The corrosive gas test was conducted by leaving it alone. Next, the contact resistance was measured by a tester and the rate of increase was calculated. With respect to the contact resistance value before the corrosive gas test, those with an increase rate of less than 20% are indicated as ◯, and those with an increase rate of 20% or more are indicated as x with a failure. Further, in order to examine the insertion characteristics of the connector, the measured and FFC pin portion by the tester, the contact resistance after repeating 30 times the insertion and removal of the connector, was calculated increasing rate with respect to the contact resistance value before insertion. Those with an increase rate of less than 20% with respect to the contact resistance value before insertion / removal are indicated as ◯, and those with an increase rate of 20% or more are indicated as x with a failure. Furthermore, after repeating the insertion and removal with the connector 30 times, the occurrence of cracks in the plating layer is observed with a microscope and no cracks are observed. As a pass, it was indicated by a cross. The results are shown in Table 1.

As shown in Examples 1 to 6 and Reference Example of Table 1, at least an Ni plating layer having a thickness of 0.3 to 1.5 μm on the copper or copper alloy wiring of the FFC terminal portion fitted to the connector, According to the present invention, which is an FFC terminal portion in which a Pd-based alloy plating layer having a thickness of 0.03 to 0.2 μm is sequentially formed, the increase rate of the contact resistance value is 20% or less even after the gas corrosion environment, and 30 times Even when the number of insertions / removals was repeated, the increase in the contact resistance value was 20% or less, and the plating layer was an FFC terminal portion in which no crack was observed. It can also be seen that the Pd-based alloy plating layer is preferably a Pd-based alloy containing 0.1 to 1% by mass of Ni or Co.

On the other hand, as shown in Comparative Examples 1 to 7, when outside the scope of the present invention, the contact resistance value after being placed in a gas corrosive environment, the contact resistance value after 30 insertions and removals with the connector, Or there was a problem in any item, such as generation of cracks after the insertion and removal. That is, when the Ni plating layer is thin as in Comparative Example 1, the contact resistance value after gas corrosion increases by 20% or more, and when the Ni plating layer is too thick as in Comparative Example 2, the connector Cracks occurred after 30 insertions and removals. Further, if the thickness of the Pd alloy plating layer becomes thinner as shown in Comparative Example 3, that a higher contact resistance value after gas corrosion environment. Further, as in Comparative Examples 4 and 5 , when the Ni or Co content in the Pd-based alloy plating layer is less than 0.1% by mass, the contact resistance value after 30 insertions / extractions increases, and there is a problem .

Next, the effect is shown about the case where Au plating layer is formed on the Pd base alloy plating layer. That is, a sample in which an Au plating layer having various thicknesses described in Table 2 was formed on a Pd-based alloy plating layer was used as a sample. Then, this sample was fitted with a non-ZIF type connector plated with Au / Ni (Au plating thickness: 0.3 μm, Ni plating thickness: 3 μm), and in an atmosphere of 10 ppm hydrogen sulfide and 85% humidity for 48 hours. The corrosive gas test was conducted by leaving it alone. Next, the contact resistance was measured by a tester and the rate of increase was calculated. With respect to the contact resistance value before the corrosive gas test, those with an increase rate of less than 20% are indicated as ◯, and those with an increase rate of 20% or more are indicated as x with a failure. Further, in order to examine the insertion characteristics of the connector, the measured and FFC pin portion by the tester, the contact resistance after repeating 30 times the insertion and removal of the connector, was calculated increasing rate with respect to the contact resistance value before insertion. Those with an increase rate of less than 20% with respect to the contact resistance value before insertion / removal are indicated as ◯, and those with an increase rate of 20% or more are indicated as x with a failure. Furthermore, when the occurrence of cracks in the plating layer after repeated insertion and removal with the connector 30 times is observed with a microscope, if no cracks are observed, it is indicated with a mark ◯, and the occurrence of cracks is observed. As a failure, it was indicated by a cross. As for the FFC pin portion performs atmospheric exposure test of 180 days, then measuring the contact resistance by a tester was calculated the rate of increase. With respect to the contact resistance value before the atmospheric exposure test, those with an increase rate of less than 20% are indicated as ◯, and those with an increase rate of 20% or more are indicated as x with a failure. The results are shown in Table 2.

As shown in Examples 7 and 8 in Table 2, at least an Ni plating layer having a thickness of 0.3 to 1.5 μm and a thickness of 0 on the copper or copper alloy wiring of the FFC terminal portion fitted to the connector Even after being placed in a gas-corrosive environment by forming an FFC terminal part in which an Au plating layer having a thickness of 0.005 to 0.20 μm is formed on a Pd-based alloy plating layer having a thickness of 0.03 to 0.2 μm The contact resistance value is 20% or less as an increase rate, and even if the insertion and removal of 30 times with the connector is repeated, the increase in the contact resistance value is 20% or less, and after the insertion and removal, there is a crack in the plating layer. It was the FFC terminal portion where there was no occurrence. Furthermore, the increase rate of the contact resistance value after the atmospheric exposure test for 180 days was 20% or less. In addition, it is preferable to use a Pd-based alloy containing 0.1 to 1% by mass of Ni or Co as the Pd-based alloy plating layer in the FFC terminal portion having this configuration.

On the other hand, when no Au plating layer was provided on the Pd-based alloy plating layer as in Example 9, the contact resistance value increased by 20% or more by the atmospheric exposure test for 180 days. Further, when the thickness of the Au plating layer was thin as in Example 10 , the contact resistance value increased by 20% or more in the atmospheric exposure test for 180 days.

  As in the present invention, the FFC terminal portion in which the Ni plating layer is applied on the copper or copper alloy wiring and the Pd-based alloy plating layer is provided thereon is excellent in corrosion resistance even when fitted to the connector and used for a long time. Moreover, since it is excellent in the insertion / extraction characteristics with the connector, it is useful for various electronic devices. Furthermore, since the FFC terminal portion in which the Au plating layer is provided on the Pd alloy plating layer has no problem with atmospheric exposure, it can be used for various electronic devices as a more excellent FFC terminal portion. .

Claims (2)

A nickel plating layer having a thickness of 0.3 to 1.5 μm is formed on the copper or copper alloy conductor , and then a thickness of 0.03 to 0.1% containing 0.1 to 1% by mass of nickel or cobalt . characterized by using a rectangular conductor which palladium based alloy plating layer of 2 [mu] m were made form the connector insertion type flexible flat cable. The palladium based alloy plating layer, the connector insertion type flexible flat cable according to claim 1, characterized in that the gold plating layer having a thickness of 0.005~0.20μm was formed.